Privacy Policy

1. What Data We Process and Where It Is Stored

At Dual N-Back (accessible at https://dualnbackapp.com), we believe in data minimization. Registration is not required to use the trainer. Cloud Sync is an optional beta feature that is enabled only after you sign in and explicitly choose what to synchronize.

A. Data Stored Locally on Your Device (Privacy-First)

Your training results, progress statistics, and preferences are stored on your device using localStorage and IndexedDB. The trainer remains local-first and works without an account or network connection. Data is transmitted to our servers only if you enable Cloud Sync; clearing site storage can delete the local copy.

• Game Statistics: Reached N-Back levels, session scores, response accuracy, and training journal entries.
• Interface Preferences: Selected language, volume, sound types, color theme, and speed settings.

B. Data Stored on Our Servers (Only via Active Requests)

Our servers store information you actively send in support requests and, if you enable Cloud Sync, the minimum information needed to provide that feature:

• Support Requests: If you use our Contact Us form, we collect your email address, the classification of the issue, your message, and basic browser metadata to help resolve your inquiry.
• Optional Cloud Sync: Account identifier, encrypted email/profile fields, encrypted training sessions, notes, journal, settings, progress and benchmark data, device/session records, revisions, deletion markers and conflict records. Session and challenge tokens are stored only as hashes.

C. De-identified Data Sent to Third-Party Processors

We use third-party analytics to understand traffic and improve usability. These services collect anonymous technical data and behavior logs:

• Google Analytics (GA4) [Google LLC, USA]: Receives de-identified IP addresses, page views, and click events to analyze global usage trends. For more details, review Google's Privacy Policy or opt out using the Google Analytics Opt-out Browser Add-on.
• Yandex Metrika [Yandex LLC, Russia]: Collects browser type, screen resolution, scroll depth, and interaction maps to fix display bugs. For more details, review Yandex's Privacy Policy.

2. How We Use and Share Information

We use your data to display progress charts, optimize the trainer for your device, and provide technical support. We guarantee that:

• Your contact details and support messages will never be sold, rented, or shared with third parties for advertising or marketing purposes.
• We do not sell or share your personal data within the meaning of the California Consumer Privacy Act (CCPA/CPRA).

3. Legal Basis for Processing (GDPR)

If you reside in the European Economic Area (EEA), our legal grounds for processing your data under GDPR include:

• Performance of a Contract: Providing you with the core functionality of the Dual N-Back trainer (saving stats and settings locally).
• Consent: When you voluntarily submit a support ticket via the contact form.
• Legitimate Interests: Improving our trainer algorithms, analyzing site usage, and ensuring website security.

4. Cookies and Local Storage

We use cookies and browser storage to maintain core functionality. If you sign in to Cloud Sync, a Secure, HttpOnly, SameSite session cookie and a CSRF cookie are used for authentication and request protection. Analytics cookies from Google and Yandex may distinguish visits. You can manage cookies in your browser; disabling them prevents Cloud Sync sign-in and may reset settings.

5. Data Retention

• Local Data: Statistics and settings remain on your physical device indefinitely until you clear your browser's cache or local storage.
• Cloud Sync: Synced content remains until you delete cloud data or the account. Sign-in sessions expire after 30 days; one-time email challenges expire after 10 minutes. Encrypted backups normally retain up to 14 snapshots; after sensitive deletion, the next successful backup replaces older snapshots.
• Support Tickets: Information submitted via contact forms is retained on our servers only for as long as necessary to resolve your request and maintain support history, up to a maximum of 12 months.

6. Your Privacy Rights & Data Deletion

Depending on your location (such as the EU/EEA under GDPR, or California under CCPA/CPRA), you have the right to access, correct, restrict, or request erasure of your data. You can exercise these rights as follows:

• To delete or request a copy of your support communication history stored on our servers, please contact us at support@dualnbackapp.com. We will process your request within 30 days.
• Local training data can be deleted by clearing site storage. If Cloud Sync is enabled, Settings also provides cloud export, cloud-data deletion, account deletion, device review and session revocation. Deleting cloud data does not delete the local copy.

7. Children's Privacy

Our service is not intended for children under the age of 13 (or 16 in the EU/EEA) without parental consent. We do not knowingly collect personal data from children. If you become aware that a child has sent us a support message containing personal data without parental guidance, please contact us to have it deleted.

8. Security and Transfers

Data is transmitted over HTTPS. Cloud Sync payloads and direct identifiers are encrypted at application level before being stored; lookup values and session credentials are hashed. OAuth sign-in may transfer limited identity data through the provider you choose (Yandex, VK, Google or Microsoft). Email sign-in uses a one-time code or link. No method can eliminate every security risk.

9. Optional Cloud Sync controls

Cloud Sync is separate from anonymous trainer use and can be left disabled. At first sign-in you can synchronize existing and new data or only new data. Offline changes are queued locally. You can sign out or revoke another device without removing local training history.

10. Contact Us

If you have any questions, feedback, or legal inquiries regarding this Privacy Policy, please contact us at:

• Email: support@dualnbackapp.com
• Contact Form: Contact Us